These asiatic acid derivatives have been prepared by modifying A-ring of asiatic acid or methyl asiatate. The modification has been already performed to decide the structural formula of asiatic acid, and reported. [B. Singh and R. P. Rastogi, Phytochemistry, 8, 917-921, 1969]
Asiatic acid and asiaticoside (trisaccharide of asiatic acid) and madecassic acid, which are compounds extracted from Centella asiatica, were isolated firstly by Bontems in 1941 [J. E. Bontems, Bull. Sci. Pharmacol., 49, 186-96 (1941)], and their structure was defined by Polonsky and his colleagues.[J. Polonsky, Compt. Rend., 232, 1878-80 (1951): J. Polonsky, Bull. Soc. Chim., 173-80 (1953)].
The extract including asiatic acid and asiaticoside from Centella asiatica have been used for treatment of hurted skin or chronic ulcer since old times, and also for treatment of skin deformation owing to tuberculosis or leprosy. [P. Boiteau, A. Buzas, E. Lederer and J. Polonsky, Bull. Soc. Chim., 31, 46-51 (1949)]
Recently, it was reported that various triterpenes which have similar structure to asiatic acid extracted from plants, in particular, ursolic acid, show effect on cytotoxicity. [K. Yasukawa, Oncology, 48, 72-76 (1991); Dominic, Y. Alex, Med. Sci. Res., 21(5), 213-215 (1993); Ryu, Shi young, Arch. Pharamacal Res., 17(5), 375-7(1994)] It was reported that betulinic acid, which can be easily synthesized from its precursor isolated from the bark of white birch, shows cytotoxicity against melanoma cells without substantial side effect. [Nat. Med., 1, 1046(1995)]